This invention relates generally to a thread convolution and more specifically to an improved lock thread convolution which retards relative rotation between it and a mating thread convolution in one direction while enabling them to freely rotate in the opposite direction relative to each other.
Fasteners are frequently utilized in environments in which the fasteners are subjected to loads or vibrations which tend to loosen the fasteners. In an effort to prevent loosening of a threaded fastener, one or more thread convolutions of the fastener have been provided with flanks having serrations or other types of projections which engage a mating thread convolution to prevent relative rotation between the thread convolutions in a reverse direction, that is in a direction tending to loosen the fastener. Various prior art fasteners having locking thread convolutions of this general type are disclosed in U.S. Pat. Nos. 3,982,575; 3,972,361; 3,972,359; 3,339,389; 3,176,746; 113,557; and U.S. Pat. No. Re. 27,678. The projections or serrations formed on the flanks of these known lock thread convolutions are relatively stiff and tend to gouge or excessively scratch the flank surface of the mating thread convolution when the two thread convolutions are interconnected.